This invention relates to a machine tool driving device suitable for use in a shearing machine, a press and other metal plate machining apparatus.
In a machine tool driving device, a synchronization mechanism plays an important role as is well known in the art, the mechanism being based on either electric or mechanical controls. This invention is specifically directed to a machine tool driving device having a mechanical synchronization mechanism.
There have been proposed various devices of this nature, for example, U.S. Pat. No. 3,157,084 where, as shown in FIG. 1, a blade 1 is integrally mounted on a tool support 2. The tool support 2 is connected by links 8 and 9 to rocking arms 4 and 5 which are pivotally supported by pins 6 and 7, respectively. The rocking arms 4 and 5 are adapted to transmit a reciprocating motion of a piston-cylinder 3 to the links 8 and 9 which, in turn, drivingly impart vertical reciprocating motion to the tool support plate 2 and the blade 1.
In the prior-art apparatus with the construction just described, however, a difficulty is often encountered in that, as the links 8 and 9 are disposed parallel to each other, the support 2 is imposed with not only a vertical force but also some horizontal force during the machining operation. This phenomenon is now discussed in greater detail with reference to FIG. 2. As is shown, the forces F and P which are applied to the support by the links 8 and 9, respectively, have vertical components F.sub.1 and P.sub.1 and horizontal components F.sub.2 and P.sub.2. The components F.sub.2 and P.sub.2, therefore, represent the horizontal force which is imposed on the support 2 during the machining operation, which can be a major drawback of this prior-art apparatus.